In short
Diverticulitis happens when small pouches that form in the colon wall become inflamed or infected, usually causing sudden lower-left abdominal pain that needs prompt evaluation.
On your report
CRP, WBC / Total Leukocyte Count
On this page
01
What's Happening in the Colon
Diverticula are small, bulging pouches that can form in the wall of the colon, most often in its lower left portion. Having them — a condition called diverticulosis — is extremely common with age and usually causes no symptoms at all; most people who have diverticula never know it.
Diverticulitis is different: it's what happens when one or more of those pouches becomes inflamed or infected, usually because a small piece of stool or debris gets trapped inside it. That shift from silent diverticula to an inflamed, painful episode is what brings people to a doctor.
02
Recognizing an Episode
The hallmark symptom is a fairly sudden, often steady ache in the lower left abdomen, sometimes worsening over a day or two, along with fever, nausea, and a change in bowel habits. Tenderness when the area is pressed is common on exam.
Severe pain, a high fever, an abdomen that feels rigid or extremely tender, or an inability to pass stool or gas can signal a complication such as a perforation or abscess, and needs emergency evaluation rather than a wait-and-see approach at home.
03
How It's Diagnosed
A CT scan of the abdomen is the standard way to confirm diverticulitis, show how many pouches are involved, and check for complications like an abscess or a small area of perforation. Blood tests, including a white blood cell count and inflammatory markers like CRP, support the diagnosis by showing active inflammation.
Because colon cancer can occasionally cause similar pain and is worth ruling out, a colonoscopy is often recommended some weeks after the inflammation has settled — not during an active flare, when the colon is too inflamed to examine safely.
04
Treatment
Mild, uncomplicated diverticulitis is often managed at home with rest, a temporary shift to a low-fiber or liquid diet while inflamed, and sometimes antibiotics, depending on how the episode looks. Pain typically starts improving within a few days.
More severe episodes, an abscess, or signs of perforation usually require hospitalization for intravenous antibiotics, drainage of an abscess, or in some cases surgery to remove the affected part of the colon. Repeated severe episodes are also a reason a colorectal surgeon may discuss elective surgery to prevent future flares.
05
Preventing Future Episodes
A high-fiber diet, once the acute episode has resolved, is the main long-term strategy, since it's linked to a lower risk of future flares — this is a reversal of older advice to avoid nuts and seeds, which current evidence doesn't support. Staying active and maintaining a healthy weight also help.
Anyone who's had one episode has some chance of another, so knowing the pattern of symptoms — and seeking care promptly rather than waiting out a bad flare — makes future episodes easier to catch and treat early.
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Sources
- Diverticulosis and Diverticulitismedlineplus.gov
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